Early and Solid Protection Afforded by the Thiverval Vaccine Provides Novel Vaccination Alternatives Against Classical Swine Fever Virus

Abstract

Classical swine fever virus (CSFV) remains a challenge for the porcine industry. Inefficient vaccination programs in some endemic areas may have contributed to the emergence of low and moderate virulence CSFV variants. This work aimed to expand and update the information about the safety and efficacy of the CSFV Thiverval-strain vaccine. Two groups of pigs were vaccinated, and a contact and control groups were also included. Animals were challenged with a highly virulent CSFV strain at 21- or 5-days post vaccination (dpv). The vaccine induced rapid and strong IFN-α response, mainly in the 5-day immunized group, and no vaccine virus transmission was detected. Vaccinated pigs showed humoral response against CSFV E2 and Erns glycoproteins, with neutralising activity, starting at 14 days post vaccination (dpv). Strong clinical protection was afforded in all the vaccinated pigs as early as 5 dpv. The vaccine controlled viral replication after challenge, showing efficient virological protection in the 21-day immunized pigs despite being housed with animals excreting high CSFV titres. These results demonstrate the high efficacy of the Thiverval strain against CSFV replication. Its early protection capacity makes it a useful alternative for emergency vaccination and a consistent tool for CSFV control worldwide.

Development of a new loop-mediated isothermal amplification test for the sensitive, rapid, and economic detection of different genotypes of Classical swine fever virus

“…Sample matrices included: nasal swab, rectal swab, mesenteric lymph node, tonsil, spleen, and sera. For genotype 1, samples obtained from a previously performed experimental infection in domestic pigs were tested ( Lamothe-Reyes et al., 2021 ). Briefly, 9-week-old pigs were infected with 10 5 TCID 50 of CSFV Margarita strain by intramuscular injection in the right neck.…”

Removal of the E rns RNase Activity and of the 3′ Untranslated Region Polyuridine Insertion in a Low-Virulence Classical Swine Fever Virus Triggers a Cytokine Storm and Lethal Disease

“…In addition, the virulence of the double mutant virus was also evaluated in six 3-week-old pigs from Pestivirus -free sows (numbered 20 to 25), as in previous studies ( 43 , 44 ). The six pigs were inoculated intranasally with 2.5 × 10 4 TCID 50 s of vPdR-H 30 K-5U.…”

The Development of Classical Swine Fever Marker Vaccines in Recent Years

“…The Thiverval strain is derived from the Alfort strain that has been continuously passed through more than 170 generations at 29-30 • C. Studies have shown that the Thiverval strain provides complete protection 5 days after inoculation, produces neutralizing antibodies 14 days after inoculation, and effectively inhibits the replication of CSFV after the attack [23]. GPE strain has 225 mutations compared with its parent ALD strain, which is also passed continuously at 30 • C [24].…”